I have two distinct issues with this plugin.
First, it seems that it does not like the way my client's theme does comments because I get none. I've switched the theme to 2013 and I get the discussion there so I know its my theme. What I need to know, then is what does the plugin expect in terms of the page comments? If I had to venture a guess, I'd say that there are assumptions about where in the theme the comments get rendered but that happens to not be the case here.
Obviously, you can't debug the theme for me but if there was a "Go look for this function/action/filter call, make sure ..." it would narrow my haystack to something managemable. The prospect of sifting through hundreds of lines of code I didn't write is not terribly appealing.
Secondly, even when I use a standard theme, the tabs disappear on the discussion and history pages. there is no markup of any kind rendered for those tabs.